.box{
    width:200px;
    height: 200px;
    background-color: aliceblue;
    opacity: 0.5;
    border: 1px solid blue;
    position: relative;
    margin: 0 auto;
    margin-bottom: 30px;
}
.r{
    position: relative;
    top: 37%;
    right: -25%;
}
.a{
    position: absolute;
    top: 30%;
    right: 10%;
}
.g{
    position: fixed;
    top: 500px;
    left: 700px;
}
body{
    background-image: url(../img/背景4.jpg);
    background-repeat: no-repeat;
    background-position: 100%;
}